Saturday, 7 March 2015

Oceanic riches

Yesterday was rather a mixed day - exploring a wonderful ravine in Snowdonia and seeing some top quality oceanic liverworts and mosses, but knowing that it would have been notified as a SSSI ten years ago but for an inadequate bryophyte survey then which suggested it wasn't up to scratch. Now it is under threat and there may not be anything that can be done because of its lack of protected status.

The ravine has a series of waterfalls, cascades and boulder chokes, and some good base-rich rock at its upper end. Previous records are of Harpalejeunea molleri and Sphenolobopsis pearsonii: I refound the former but missed the latter. More tantalising was a 19th century record of Paraleptodontium recurvifolium, which has old records from 10+ N Wales sites but recent ones from just 2 or 3 and it's possible that some/many/all of these result from misidentification of the related Oxystegus daldinianus (until recently considered an extreme form of Trichostomum tenuirostre). There's a lot of O. dalinianus in the ravine, but no sign of Paraleptodontium.

As well as Harpalejeunea, which was abundant over ca 8x1m of a base-rich rockface and also occurred on a boulder downstream, there was one rock covered with Drepanolejeunea hamatifolia (a new site) and another with a few tufts of Colura calyptrifolia (also a new site). Whereas Colura is now commonplace on trees in southern Wales, it remains very rare on rocks in its traditional ravine habitat.

Highlight of the day was spotting a patch of Bartramia halleriana about 3m up the ravine side, below which were a few fallen tufts growing among Hyocomium. This is the first SH64 record of this Nationally Scarce moss.